A hard-disk drive (HDD) is a non-volatile storage device that is housed in a protective enclosure and stores digitally encoded data on one or more circular disks having magnetic surfaces. When an HDD is in operation, each magnetic-recording disk is rapidly rotated by a spindle system. Data is read from and written to a magnetic-recording disk using a read-write head that is positioned over a specific location of a disk by an actuator. A read-write head uses a magnetic field to read data from and write data to the surface of a magnetic-recording disk. A write head makes use of the electricity flowing through a coil, which produces a magnetic field. Electrical pulses are sent to the write head, with different patterns of positive and negative currents. The current in the coil of the write head induces a magnetic field across the gap between the head and the magnetic disk, which in turn magnetizes a small area on the recording medium.
Increasing areal density (a measure of the quantity of information bits that can be stored on a given area of disk surface) is one of the ever-present goals of hard disk drive design evolution, and has led to the necessary development and implementation of various means for reducing the disk area needed to record a bit of information. One such development involves the use of a new recording paradigm referred to as shingled magnetic recording (SMR), which utilizes a data writing technique in which data tracks partially overlap, similar to shingles on a roof. Because the data tracks are written to disk sequentially in an overlapping manner, updates of individual tracks or sectors may require a read and rewrite of an entire band of shingled tracks. Furthermore, a “write verify” function, which causes write operations to be verified by an immediate follow-up read operation, may be utilized to ensure data reliability. However, the write verify function decreases write command throughput because of this additional data verification procedure. For example, write command throughput with the write verify function might result in loss of performance of more than 55% as compared to a write operation without the write verify function.
Any approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.